(i) Field of the Invention
The invention relates broadly to an improved apparatus and process for cutting elongated material, such as filamentary tows, into predetermined lengths, such as staple fiber. More particularly, it relates to an improvement to the means for holding the plurality of knife edges.
(ii) Prior Art
FIGS. 1-4 (Prior Art) of this application are essentially identical to FIGS. 1-4 of U.S. Pat. No. 3,485,120 (Keith), "Method and Apparatus for Cutting Elongated Material". With reference to these Figures, U.S. Pat. No. 3,485,120 discloses an apparatus for cutting material such as filamentary tows (64) into predetermined lengths comprising (a) a cutting assembly (18) including a plurality of spaced apart knife (28) edges (30) secured to a mounting member (22) at equal radial distances from a point on said mounting member (22) thereby forming a reel (18), each of said radial distances in every instance being less than the distance from said point to the periphery of said mounting member (22); (b) said cutting assembly (18) having means adapted to receive successive wrappings of material to be cut (64) in contact with a plurality of said knife (28) edges (30) so that no relative movement occurs between said material and said knife (28) edges (30) longitudinally of said material; and (c) means for forcing said material between adjacent knife (28) edges (30) [presser roll (42)], thereby severing said material into lengths of controlled dimensions. A more detailed description will be found in U.S. Pat. No. 3,485,120, particularly columns 3 and 4.
FIG. 3 (Prior Art) shows a gap between the top of the knives (28) and the bottom of the annular cap (36) which "protects" the upper end of blades (28).
U.S. Pat. No. 3,733,945 is a patent of improvement relative to forementioned U.S. Pat. No. 3,485,120, and is particularly directed to the use of a stream of air to remove cut fibers from the apparatus.
In addition, there has been public use for more than one year of the cutter reel shown in FIG. 11 (Prior Art). In the sandwich construction the knife (400) is bevelled at the top and the upper ring (236) is bevelled at the bottom. Accordingly, the upper ring prevents some (probably 3) of the knives from moving in a direction longitudinal of the knife edges. However, most of the knives are free to move at least a small amount in a direction longitudinal of the knife edges, on account of variations in length of the knives and other tolerances causing both Gap A and Gap B in FIG. 11 to be greater than zero.
None of the foregoing prior art has means for preventing all movement of at least most of the knives in an upwards direction longitudinal of the knife edges.